Backyard plans

I am trying to focus on finishing up some of my projects - the path next to the retaining wall on the east side of the garage and finishing the front path on the west side of the house.  I came up with a wonderful plan for that space - instead of putting in a round patio, I am just going to edge a circle of grass with bricks.  The grass there is nice, so why dig it up?  Then I will extend the front border so that it provides a private space (well, when the shrubs grow up, that is.)  It will be my "secret garden."  And my front path will have the destination it needs. 

The big thing on my mind is the back yard.  It is just such a large area and I really need a good plan.  I have some ideas of what I want, but am struggling with how to integrate them.  I am reading P. Allen Smith's book on garden rooms - they are lovely, but all those hedges would require so much maintenance - and they are very formal.   But some separation of the space is definitely needed!

So I keep pondering.......